At which level does each common carotid artery divide?

• A. Thyroid cartilage
• B. C3 vertebra
• C. C5 vertebra
• D. C4 vertebra

Answer: (D)

The common carotid artery divides into the internal and external carotid arteries at the level of the C4 vertebra. This anatomical landmark is significant in medical practice, particularly in interventions related to neck and head vascular procedures, as it helps in locating the vessels accurately for imaging or surgical purposes.

The division generally occurs around the upper border of the thyroid cartilage, which can vary slightly among individuals, but is consistently around C4 in most people. This level is important for clinicians to know, as it allows for appropriate assessment of blood supply to the brain and face and informs decisions during procedures like carotid endarterectomy or the placement of vascular stents.

In anatomical terms, the division at C4 ensures that the internal carotid artery ascends into the skull to supply the brain, while the external carotid artery supplies the face and neck. Understanding this anatomical relationship is crucial for effective diagnosis and treatment in interventional radiology and other healthcare practices focused on vascular health.